How about various Amiga transputer expansions (and systems)? I guess none of them were publically released. Not sure though... Anyway, I remember reading an article in an old finnish mag long ago, and it sure seemed quite interesting, but I couldn't help wondering why I hadn't heard / read of them before (as it was an old mag) - close enough to "Vapor" to me :-)
See for example
this one:
Search
http://www.amiga-hardware.com with "transputer" to find more.
